Climate change and disease

• According to WHO, the health effects of a rapidly changing climate are likely to be overwhelmingly negative, particularly in the poorest communities, which have contributed least to greenhouse gas emissions.
  

• Some of the health effects include:
  
  • Increasing frequencies of heatwaves: recent analyses show that human-induced climate change significantly increased the likelihood of the European summer heatwave of 2003.
    
  • More variable precipitation patterns are likely to compromise the supply of freshwater, increasing risks of water-borne disease.
    
  • Rising temperatures and variable precipitation are likely to decrease the production of staple foods in many of the poorest regions, increasing risks of malnutrition.
    
  • Changes in climate are likely to lengthen the transmission seasons of important insect-borne diseases such as malaria, dengue fever and yellow fever, and rodent-borne diseases like typhus and plague, and to alter their geographic range, potentially bringing them to regions which lack either population immunity or a strong public health infrastructure.
  
  

  
  Rats and rodents thrive in degraded environments
  � Mark Edwards/Still Pictures
  

• Harvard Medical School has recently linked outbreaks of dengue fever, malaria and hantavirus in the United States to climate change.
  

• Malaria, a disease transmitted by the Anopheles mosquito, is restricted to humid regions with average temperatures above 16�C (61�F), covering around 45 per cent of the world at present. Global warming will inevitably expand the mosquito's range, putting millions more people at risk of the disease.

• An increase in extreme weather events - such as floods and droughts - will have serious repercussions for human health. For example, floods will help to spread water-borne diseases. Conversely, droughts might help diseases like West Nile virus. (see Section on Health and Pollution)
  

• A WHO assessment concluded that the effects of the climate change that has occurred since the mid-1970s may have caused over 150,000 deaths in 2000. It also concluded that these impacts are likely to increase in the future.
  

• According to a report by the Pew Center on Global Climate Change, global warming could exacerbate health risks for the elderly, the sick and the poor. If climate change results in more heat waves, and worse air pollution, then these groups are most at risk.

Related links:

• WHO's Factsheet on Climate and Health
  

• Climate change and pollution are killing millions, says study
  

• Spreading diseases linked to environmental decline
  

• Climate change 'will hit Africa hardest'
  

• 'Malaria is creeping up the mountains'

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